Computer-Aided Design (“CAD”) tools can improve the efficiency of the integrated circuit (“IC”) design process. For example, CAD tools may assist an IC designer with defining the physical layout of an IC by enabling the IC designer to generate a virtual version of the physical layout. For example, a designer may use CAD tools to define paths and route IC elements. CAD tools may also assist a designer perform timing analysis.
An IC design may include one or more metal elements. Traditional IC designs may define a design rule that includes using a fixed metal width and a fixed spacing between two metal elements. For example, the design rule may include a 50-50 metal width to metal spacing design rule. According to a 50-50 ratio rule, the width of spacing between two metal elements is the same as the width of each of the metal elements.
Once a minimum width is defined, the corresponding design rule is applied to the entire design. However, using a fixed metal width may cause timing issues with respect to certain paths. For example, if the critical dimension (“CD”) of a metal element is too small, then Resistivity (“R”) may cause a timing issue. On the other hand, if the CD of a metal element is too large, then Capacitance (“C”) may cause a timing issue. Thus, it would be beneficial to provide a way to enable the modification of a metal width during the design phase of an IC.